Biomaterials
Course overview
Lecture 1: Introduction to Biomaterials
BIOMATERIALS
3
Objective
◼
Define biomaterials
◼
Describe biomaterial applications
◼
Define and describe biocompatibility principle
◼
Explain factors contribute to the
performance of biomaterials in the body.
What is it biomaterial?
◼ A material intended to interface with biological systems to evaluate, treat, augment, or replace any tissue, organ or function of the body (Williams, 1999).
◼ Any substance (other than drugs) or combination of substance , synthetic or natural origin, which can be used for any period of time, as a whole or as a part of a system which treats, augments, or replace any tissue, organ or function of the body.
5
◼ A biomaterial is any material, natural or man- made, that comprises whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function "
◼ “A systemically and pharmacologically inert substance designed for implantation within or incorporation with living system nosmelC ehT( ”
slairetamoiB rof draoB yrosivda ytisrevinU (.
What is it biomaterial?
Biomaterial
Application in
Human Body
7
9
Current status of the field
◼
Today, biomaterials represent a
significant portion of the healthcare
industry, with an estimated market size of over $9 billion per year in the United
States.
◼ Cardiovascular area:
◼ approximately 100,00
replacement heart valves and
300,000 vascular graft implanted per year in US.
◼ Artificial joints replacements:
◼ Over 500,000 artificial joint
replacements, such as knee or hip, are implanted yearly in United
States.
Current status of the field
11
Future Directions
◼
Starting 1960s-1970s
◼ The first generation of biomaterials was
designed to be inert, or not reactive with the body
◼ Decreasing the potential for negative immune response to the implant.
◼
In 1990’s until now
◼ Materials designed to be bioactive, interacting in positive manner with the body to promote localized healing.
◼
Development of “smart” material which can help guide the biological response in the implant area.
◼
Design of injectable materials that can applied locally and with minimal pain to the patient.
◼
New set of nano-structured biomaterials for nano-scale objects as reinforcing
Future Directions
13
Application of Biomaterials
◼ Biomaterials that will be used may be considered from the point of view of the problem area that is to be solved:
Problem Area Examples
Replacement of diseased or damaged part
Assist in healing Improve function
Correct functional abnormality Correct cosmetic problem
Aids to diagnosis Aid to treatment
Artificial hip joint, kidney dialysis machine
Sutures, bone plates, and screws Cardiac pacemaker, intraocular lens, cochlear implant
Cardiac pacemaker
Breast implant, soft tissue augmentation, chin augmentation
Probes, catheter Catheters, drains
Application of Biomaterials
◼ Biomaterials that will be used may be considered from the point of view of the organ that will need to be replaced or improve:
Organ Heart
Heart Lung Eye Ear Bone Kidney
Cardiac pacemaker, artificial heart valve, total artificial heart Oxygenator machine
Contact lens, intraocular lens Cochlear implant
Bone plate, screw
Kidney dialysis machine
15
◼
Biomaterials are classified as:
◼ Organic if contain carbon
◼ Inorganic if they do not.
◼
More specifically biomaterials fall into one of three of materials:
◼ Metals (inorganic material)
◼ Ceramics(inorganic material)
◼ Polymers (organic material)
Type of Biomaterials
17
Type of Biomaterials
Materials Advantages Disadvantages Examples Polymers
Nylon,
Polyethylene, Silicone ,
Teflon, Dacron, Acrylates, PGA, PLA
Resilient, Easy to fabricate
Not Strong, Deforms with time ,
may degrade
Sutures ,
vascular graft , hip socket, intraocular lenses
Metals
Titanium and its alloys ,
Co-Cr alloys, stainless steel, Gold
Strong , Tough, Ductile
May corrode, Dense,
Difficult to make
Joint
replacement,
Bone plates and screws ,
Dental root implant
Type of Biomaterials
Materials Advantages Disadvantages Examples Ceramics
Aluminum oxide, Calcium
phosphates, Carbon
Very
biocompatible, Inert,
Strong in compression
Brittle,
Not resilient , Difficult to make
Dental implant, Femoral head of hip replacement, Coating of
dental and orthopedic implants Composites
Carbon-carbon
Ceramic-polymer Strong ,
less stiff than metals,
Difficult to make,
Weak in tension Joint implants Dental fillings
19
Performance of biomaterials
◼
The success of biomaterials in the body depends on factors such as:
◼ Material properties
◼ Design of the implants
◼ Biocompatibility of the materials
◼ Technique used by the surgeon
◼ Health and condition of the patient
◼ Patient activities
The Concept of Biocompatibility
◼
Definition of biocompatibility:
“Biocompatibility is the ability of a material to perform with an appropriate host response in a specific application mailliW( ”1987).
21
The Concept of Biocompatibility
◼
Biocompatibility characteristic:
◼ Biocompatibility involves the acceptance of an artificial implant by the surrounding tissues and by the body as a whole.
◼ Biocompatible materials
◼ Do not irritate the surrounding structures
◼ Do not provoke an abnormal inflammatory response
◼ Do not incite allergic or immunologic reactions
◼ Do not cause cancer
The Concept of Biocompatibility
◼ Biocompatible materials have adequate mechanical properties.
◼ Biocompatible materials have appropriate optical properties (eye).
◼ Biocompatible materials have appropriate density.
23
Examples of Biomaterials application
◼
Artificial hip joint
◼ Needed because natural joint wear out.
◼ Replacement hip joint are
implanted in more than 90 000 humans each year in US.
◼ Fabricated from titanium,
ceramics, composite, UHMWPE.
◼ After 10-15 years, the implant may loose, require another
operation.
25
Examples of Biomaterials application
◼ Prosthetic Heart valve
◼ Fabricated from carbon, metal, elastomers, fabrics, natural valves and tissue chemically pre-treated.
◼
Show good performance as soon as the valve is implanted but have some
problems:
◼ Degeneration of tissue
◼ Mechanical failure
◼ Postoperative infection
◼ Induction of blood cloth
27
Examples of Biomaterials application
◼ Intraocular lenses (IOL)
◼ Used to replace a natural lense when it become cloudy due to cataract formation.
◼ Fabricated of poly (methyl
methacrylate), silicone elastomer, soft acrylic polymers or hydrogels.
◼ Complication: IOL stimulate
outgrowth cells from the posterior lens capsule → cloud the vision.
29
31
